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First Airarc Experience

01-18-2008, 09:02 AM

I got out my K4000 and some 3/16 air arcing rods yesterday and worked with it for the first time. I donít have anyone around to show me the ropes so, I have to learn on my own. Naturally, I have a few questions.

I ran the 3/16 rods at from 175 to 250 Amps on my TB302 in electrode positive. My compressor is 175cfm rotary screw Ingersol-Rand. I have no idea how much air I was putting out, but Iím sure it was enough. One of my questions is can you use too much air?

At 250 Amps, everything started out fine, but the rod began to glow red at the tip and before long, it would grow to about an inch long and would no longer hold an arc. The rod also tended to glow red near the holder. BTW, am I supposed to clamp the non-coated end? I thought I was running too hot, so I backed down to 225, 200 and then 175. The rod didnít glow as much, but the arc wasnít as good.

I uncoiled my cables so I would have any inductance issues. The TB302 lugged down a bit at 250 Amps, but not too bad and my 1/0 cables didnít even get warm.

200-250 amps for 3/16" rod should be just about perfect. Clamp the copper coated end about 6-8" from the pointed end. This is very important and something that is often done wrong by first timers-----make sure that the air flow is between the rod and the workpiece! If you have the air flow over the top of the rod the results are not real good. Keeping your cables uncoiled is also a good practice.

As for air volume all you need is enough to blow the molten metal out of the groove. More is not always better! Make sure where the "fire" is going to go or you may end up with a real fire!

With a little practice you will find an air-arc to be a valuable tool for welding repairs.

Flash me! I'm a welder.

American by birth, Union by choice! Boilermakers Local 60

America is a Union

Comment

Well, I made the typical rookie mistake and clamped the rod at the very end and the uncoated end at that. I was using it like a standard welding rod. I guess you clamp it more towards the middle to keep the rod from burning up and as you use the rod up, you must move the rod holder further away?

I don't fully understand why the rod has a copper coating on all but the tip. But from what you are saying, the uncoated end is where you strike the arc from.

Even with my mistakes, I was able to gouge welds out that would have been difficult to do with a oxy/act torch. Other than it took me forever to coil my cables back up, it was quicker than anything else to do the job.

Comment

Rods are copper clad to give better contact with the rod. As you burn the rod the copper melts away to prevent contaminating the metal. If you see any copper or carbon residue on the steel you will want to remove it with a light grinding before welding.

You will soon discover how long to stick your rod out as you cut. Try to avoid sticking your rod. In no time you will be able to run a smooth continuous arc as you cut.

One other thing to keep in mind is your duty cycle. It can be easy to exceed on a 60% or less machine and that is a real killer for a welding machine.

Flash me! I'm a welder.

American by birth, Union by choice! Boilermakers Local 60

America is a Union

Comment

Not to beat a dead horse but what the other posts said is correct and with a little practice you will find that you can use the airarc just like a potatoe peeler, you can control depth and width and peel old weld right off real slick like, besides that its like having the power of fire and brimstone right in your hand LOL!!

Comment

All that I will add, it try to aim the air arc towards the piece to be replaced. That way, you will not be removing material from the piece that you wish to re-use.

Take care where you place your air jets - they should be behind the arc in the direction of travel, so that the molten metal is forced away from the workpiece. Example - if you are moving right to left, the air jets should be on the right side of the carbon. Slag will be blown to the left ahead of the carbon.

While you are gouging, look for a seperation line - the point where the two parent metals physically come in contact with each other. Once you have uncovered this, your job is done. If you clearly uncover the seperation line on all sides, the two pieces will fall apart, like they were never welded.

Quick touch up with a grinder, and you are ready to re-assemble.

I use my Air Arc just about every day, in all sorts of applications. When you get comfortable with it, and have some helmet time, you will be able to wick away welds with all the finesse of a surgeon.

Enjoy.

Later,
Jason

Professional Spark Generator by Trade.

Comment

I got out my K4000 and some 3/16 air arcing rods yesterday and worked with it for the first time. I donít have anyone around to show me the ropes so, I have to learn on my own. Naturally, I have a few questions.

I ran the 3/16 rods at from 175 to 250 Amps on my TB302 in electrode positive. My compressor is 175cfm rotary screw Ingersol-Rand. I have no idea how much air I was putting out, but Iím sure it was enough. One of my questions is can you use too much air?

At 250 Amps, everything started out fine, but the rod began to glow red at the tip and before long, it would grow to about an inch long and would no longer hold an arc. The rod also tended to glow red near the holder. BTW, am I supposed to clamp the non-coated end? I thought I was running too hot, so I backed down to 225, 200 and then 175. The rod didnít glow as much, but the arc wasnít as good.

I uncoiled my cables so I would have any inductance issues. The TB302 lugged down a bit at 250 Amps, but not too bad and my 1/0 cables didnít even get warm.

Any feedback would be appreciated.

Thanks.

The extra things that I might add is to make sure your air hose is out of the way of the molten metal as it is falling and may pile up near your hose. A good ground is a must even if you are burning with a champher rod. Your lead could get really hot and may start to melt down if your ground isn't good. If you plan on doing any air arcing such as under trailers or any time that you need to be moving around, have your air arc rods in something like a piece of pvc with a screw on cap so that they won't break as you and moving around. The air arc cutting system is a really good system and I use it along with my plasma cutter powered from my miller 250 trail blazer. It is possible to cut nuts off from bolts without damaging the threads. Have fun and wear ear plugs and a resperator.

Comment

One thing in regard to your question about how much air. I think your manual says max. air pressure is 80 psi @ 24cfm ???? I think - check manual. I connected my air to the shop air where I was working instead of my truck compressor and was surprised how far that plastic air valve could go. Never did find all the parts Found out their line pressure was 150lbs.+ they said for filling their truck tires Just watch the pressure. With all the other tips you will catch on fast. Ear plugs are good- besides the noise they help keep the hot berries out